Problem: Evaluate the following expression when $b = 1$ and $a = 5$. $8$ $b$ $ + 6$ $a$ $ - 9$
Answer: Substitute $1$ for ${b}$ and $5$ for ${a}$ $ = 8{(1)} + 6{(5)} - 9 $ $ = 8 + 30 - 9 $ $ = 29$